Corneal Pocket Research Articles

Study of comparison of surgically induced astigmatism after small incision cataract surgery and phacoemulsification surgery

To compare surgically induced astigmatism after manual small incision cataract surgery and phacoemulsification surgery. 2) To know the prevalence of pre-existing astigmatism, it’s magnitude and type and patients with cataract. 3) To calculate the average astigmatism induced after manual small incision cataract surgery and also to know the type of astigmatism and change in it in first month of surgery. 4) To calculate the average astigmatism induced after phacoemulsification surgery and also to know the type of astigmatism and change in its first month of surgery. 5) To study changes in astigmatism and its effect on vision after cataract surgery. 6) To compare astigmatism induced by straight and frown incision after operation.The study was carried out in Department of Ophthalmology, P.D.U government Medical College, Rajkot under guidance of operating surgeons and patients operated in the duration of 24 months from September 2020 to October 2022.Informed consent was obtained from all the patients undergoing study. It was a prospective study and all the patients were randomly selected over the above mentioned period that had cataract with normal anterior and posterior segments. To have a more homogeneous study population all the patients underwent a similar Preoperative, Intra operative, Postoperative Surgical protocols. All eyes were operated under peribulbar anaesthesia with 2% lignocaine+bupivacain+hyalronidase. Superior sclero corneal pocket tunnel with external incision of frown configuration in manual SICS and straight incision in phacoemulsification was made. All the cases with 3.2 mm of incision in phacoemulsification and 6.5 mm incision in manual SICS were taken. Surgically induced astigmatism was then calculated by the subtraction method and vector analysis.Average SIA in SICS was 1.32 SD and in Phacoemulsification was 0.60 SD which means that larger incision size increases SIA. SIA was maximum on first post-operative day and it regressed with time as noted on first post-operative month in both the groups. It decreased from 1.66 D on first postoperative day to 1.32 D on first postoperative month in SICS Patients and from 0.63 D to 0.60 D in Phacoemulsification patient.

Comparison between MyoRing and 355°KERATACx in the management of keratoconus

Background Intracorneal implants have been proposed over the years as a possible easier way for managing keratoconus, having a favorable influence on the course of the disease. KERATACx is a relatively new form of intracorneal ring segments that has been recently introduced but not thoroughly studied regarding its safety and efficacy. Moreover, implanting a complete intrastromal ring into a corneal pocket, MyoRing (Dioptex GmbH, Austria), is an alternative technique, which can be considered safe, effective, and relatively easy for the treatment of keratoconus. Aim To compare between the effect of MyoRing and KERATACx corneal implants as new modalities of treatment on the visual acuity, as well as assess corneal topography findings in cases with moderate to severe keratoconus. Patients and methods Our study is a prospective comparative study conducted at specialized eye centers in Cairo. A total of 20 keratoconic eyes were eventually recruited. Overall, 10 of those eyes had 355° intracorneal ring segment implants (KERATACx ring segments) inserted into a femtosecond laser-created corneal tunnel at a depth of 75% of the thinnest location at the proposed tunnel site (group A), whereas the other 10 eyes had complete ring (MyoRing) implantation into a femtosecond laser-created corneal pocket at a 300-μm corneal depth (group B), by the same designated surgeon. The study was approved by the Ethics Committee of Ain-Shams University. Results Both types were proven to be statistically effective, with no statistically significant differences between the two groups related to any of the followed up parameters. In fact, both proved safe, effective, and reliable methods for managing keratoconus, with no difference of importance even to the degree of myopic refractive error correction. There were no significant intraoperative or postoperative complications reported within both groups throughout the whole study and follow-up period, but in turn, stability of the achieved results was found in both groups. Conclusion Both MyoRing and KERATACx were found to be equally effective, safe, and reliable methods for keratoconus management.

Possible use of corneal lenticule in surgery of corneal diseases (literature review)

In this review, we analyzed the domestic and foreign literature on the use of corneal lenticula obtained by keratorefractive surgery using the SMILE technology (SMall Incision Lenticula Extraction). Research is being actively carried out on the use of a lenticular tissue for refractive purposes: for the correction of hyperopia (LIKE – Lenticular Intrastromal Keratoplasty), for the correction of presbyopia (PEARL – PrEsbyopic Allogenic Refractive Lenticule). A significant amount of works are devoted to the use of lenticular tissue for the treatment of keratectasias of various origins. For example, a number of authors for the treatment of keratoconus suggest implantation of a lenticule into the recipient’s corneal pocket formed by a femtolaser (SLAK – Stromal lenticule addition keratoplasty). Clinical cases of combined treatment are described: implantation of a lenticule and corneal intrastromal segments for the treatment of corneal pellucid degeneration. A large number of works are devoted to the use of lenticules for tectonic coverage of ulcerative defects, marginal thinning in Mooren’s ulcer. Several clinical cases of the use of a corneal lenticule to cover a deep corneal defect in recurrent pterygium are described. This review also included articles on the storage and decellularization of corneal lenticules. The analyzed articles show a wide area of application of the corneal lenticule; however, more research is required in each of the areas of application, and it is also necessary to solve the problem of procurement and storage of lenticular tissue.

Femtosecond Intrastromal Lenticule Implantation (FILI) for Management of Moderate to High Hyperopia: 5-Year Outcomes.

To report the long-term clinical experience following femtosecond intrastromal lenticule implantation (FILI) for the management of moderate to high hyperopia. Eligible patients who underwent FILI for moderate to high hyperopia from July 2013 to October 2020 were included. A donor small incision lenticule extraction lenticule, matched for refractive error, was implanted into the recipient's corneal pocket created using a femtosecond laser at 160 µm depth. Visual and refractive outcomes and long-term complications were evaluated at the end of a mean follow-up of 68 ± 17.28 months (5.6 years). Forty-two eyes of 25 patients (mean age: 27.29 ± 5.52 years) were analyzed. The mean spherical equivalent reduced significantly from +5.50 ± 1.96 to +0.66 ± 1.17 diopters (D) at last follow-up visit. Thirty eyes (71%) were within ±1.00 D of spherical equivalent correction. Cumulative uncorrected distance visual acuity of 20/40 or better was achieved in 34 eyes (81%). Efficacy and safety indices were 0.86 ± 0.19 and 1.17 ± 0.39, respectively. There was a significant increase in mean keratometry (Kmean) anterior, central corneal thickness, Q-value, and corneal higher order aberrations and a decrease in Kmean posterior 2 weeks postoperatively, without any significant change in these parameters thereafter (P > .05). Four eyes of 3 patients underwent enhancement and another 4 eyes underwent explantation of the lenticule followed by exchange (2 eyes) and hyperopic laser in situ keratomileusis (2 eyes). No eye lost more than one line of CDVA. At 5 years of follow-up, FILI for moderate to high hyperopia showed good safety, efficacy, and reversibility. Modification of nomograms and surgical planning may be employed for further refinement of the outcomes. [J Refract Surg. 2022;38(6):348-354.].

Refractive corneal inlay implantation outcomes: a preliminary systematic review.

To review all case series of refractive corneal inlay implantation: Flexivue (Presbia, Netherlands), Invue (BioVision, Brügg, Switzerland) and Icolens (Neoptics, Hünenberg, Switzerland) performed in presbyopia patients and to evaluate the reported visual outcomes. In addition, our aim is to provide assessment for complications and to report the satisfaction rates. PubMed, Web of Science and Scopus databases were consulted using "refractive corneal inlay", "Flexivue Inlay", "Invue Inlay" and "Icolens inlay" as keywords. 147 articles were found, and they were assessed considering the inclusion and exclusion criteria. After filtering, this systemic review included ten articles, published between 2011 and 2020. 308 eyes from 308 participants were enrolled in this systematic review. Mean maximum follow-up was 13.9months. Nine of the ten case series included used femtosecond laser for the corneal pocket creation. Mean pocket depth was 293.75µm. 77.5% of the eyes reported a postoperative uncorrected near visual acuity of 20/32 or better, and 19.20% of the inlay-implanted eyes achieved an uncorrected distance visual acuity of 20/20 or better. The most prominent complications were halos, pain, photophobia, and poor distance visual acuity. 27 eyes (8.7%) had to be explanted due to complications, such as near-distance spectacle dependence or blurred distance vision. Refractive corneal inlay outcomes demonstrated high efficacy, safety, and satisfaction rates. Furthermore, it is a reversible technique. However, the findings must be viewed with caution due potential conflict of interest. Further research with higher sample size is needed to validate these findings.

Intracorneal scleral patch supported cyanoacrylate application for corneal perforations secondary to rheumatoid arthritis.

Purpose:To describe a new technique of intracorneal scleral patch (ICSP) supported cyanoacrylate tissue adhesive (CTA) application in corneal perforations, greater than 3.0 mm secondary to rheumatoid arthritis (RA).Methods:This Prospective, non-randomized, non-comparative, interventional series included 14 eyes (14 patients). All patients had corneal perforations sized 3.5 to 4.5 mm due to RA, which were treated with ICSP supported CTA application. A partial thickness scleral patch 1.0 mm larger than diameter of corneal perforation was prepared. A lamellar corneal pocket 0.5 mm all around the corneal perforation was created. The partial thickness scleral patch was placed in the corneal perforation site and the edge was fitted into the lamellar intracorneal pocket. A minimum quantity of CTA was applied on the scleral patch to seal the perforation.Results:The corneal perforations healed in 14 eyes (100%) in a mean 7.71 ± 1.14 (range, 6–9) weeks. One eye (7.14%) had inadvertent extrusion of ICSP due to premature removal of CTA but, Seidel's test was negative, and the corneal epithelial defect healed with BCL alone. One eye each (7.14%) developed steroid induced cataract and glaucoma. None of eyes developed infective keratitis, re-opening of corneal perforation (necessitating repeat procedure) or enlargement of corneal perforation requiring penetrating keratoplasty (PKP).Conclusion:ICSP supported CTA application is a successful alternative option to emergency PKP in treating corneal perforations sized 3.5 to 4.5 mm with associated RA.

Использование фемтосекундрого лазера VisuMax для проведения кросслинкинга роговичного коллагена

Introduction. Corneal collagen crosslinking is a treatment method of advanced keratoconus, improving a «compaction» thickness or increasing a strength of corneal stroma. The high functional results and the shortened postoperative periods in patients during crosslinking using a femtosecond laser determine the prospects for a further study of this trend. Purpose. To study the conditions and to apply the femtocrosslinking method based on the standard flap formation options using the VisuMax femtolaser device. Material and methods . There were 20 patients under our observation with progressive keratoconus (20 eyes) who underwent femto cross-linking of corneal collagen using a VisuMax femto-laser. All patients were examined using the standard preoperative ophthalmologic methods (visometry, tonometry, keratorefractometry, pachymetry, keratotopography). The fact of progression of keratoconus was established on the basis of dynamic fellow-up for at least 6 months. Results. Features of the method of femto-cross-linking of corneal collagen using the VisuMax are: 1) extension of the flap leg in the operating settings (the angular size of the bridge increased to 320°); 2) formation of the circular corneal pocket parallel to the front surface via the femto-laser and one arcuate corneal incision depth of 140–160 µm, and the diameter of the pocket and the arcuate cut – 7.9–8.7 mm.All patients (20 eyes, 100%) were achieved the stabilization of ecstatic process within the follow-up period of 6 and 12 months. Conclusion. The conditions for the use of a laser installation VisuMax (Carl Zeiss) using the «FLAP» program in the operation of corneal collagen femtocroslinking have been determined. The advantage of this method is to simplify the classical way of doing cross-linking and increase its effectiveness. Promising is the further study of technology, dynamic control over patients and long-term results.

Two-year observation of morphologic and histopathologic changes in the monkey cornea following small incision allogenic lenticule implantation

PurposeTo observe the morphologic and histopathologic changes of femtosecond laser assisted small incision allogenic intrastromal lenticule implantation (AILI) in monkey corneas. Methods6 healthy adult monkeys were included. One eye of two monkeys and both eyes of one monkey received femtosecond lenticule extraction with a −4.0 diopter (D) correction. Each extracted refractive donor lenticule was immediately allogeneically transplanted into a corneal stromal pocket created by a femtosecond laser in another monkey's eye. A postoperative two-year follow-up was performed with slit lamp microscopy, corneal topography, anterior segment optical coherence tomography and in vivo confocal microscopy. All eyes were enucleated for Hematoxylin-Eosin staining and transmission electron microscopy (TEM) observation. ResultsNo complications were observed in the follow-up period. At postoperative 2 years, the corneas remained clear and the lenticules were integrated with the surrounding tissue under slit lamp microscopy. Nerve fiber regeneration was detected in the lenticule layer as observed through confocal microscopy. Corneal power was increased by 1.83 ± 1.36 D after 2 years, which was less than at 6 months (3.27 ± 1.2 D). Disordered fibers and decreased keratocytes in the implanted lenticules could be detected under light microscopy and TEM, with a clear boundary between the lenticules and the surrounding tissue. ConclusionsSmall incision AILI is feasible and safe for reshaping the cornea. Corneal healing remained stable while refraction showed a moderate regression within postoperative 2 years.

MyoRing Implantation in Comparison with MyoRing Implantation Combined with Corneal Collagen Crosslinking for Keratoconus

Purpose: tо estimate the effectiveness of complete corneal ring (MyoRing) implantation compared with MyoRing implantation combined with corneal collagen crosslinking (CXL) for keratoconus treatment for 36 months follow-up. Patients and Methods. There were 101 patients (124 eyes) with progressing keratoconus aged 18–59 years in the study. Intracorneal rings were implanted in all patients. The patients were divided into 2 groups. MyoRing implantation was performed in a series of 59 patients (76 eyes) with keratoconus II–III Amsler classification, 42 patients (48 eyes) had MyoRing implantation combined with CXL. Implantation of a MyoRing in the corneal pocket was performed using a PocketMaker microkeratome and corneal intrastromal implantation system. Results. Keratometry was reduced in both groups; after MyoRing implantation for 8,45 D and MyoRing combined with CXL for 7,44 D, the spherical equivalent decreased for 7,72 and 6,29 D respectively, after 36 months. The cylinder decreased to 3,33 D with MyoRing alone and to 3,11 D with MyoRing combined with CXL. The smallest corneal thickness remained stable during 36 months after the procedure. There was an improvement in uncorrected and corrected visual acuity, and the difference in the CRF within the period of up to 12 months after the operation. It can be explained by the pseudochase formation in the group with a combined procedure. Conclusion. The implantation of the MyoRing IRC and the combination of MyoRing with CXL showed efficacy and safety in stabilizing keratoconus stabilization, as well as correction of comorbided ametropia 3 years after surgery. Both MyoRing implantation and MyoRing combined with CXL were effective in the stabilization of progressive keratoconus, as well as the correction of ametropia 3 years after surgery. There was no significant difference in MyoRing implantation and its combination with corneal crosslinking in visual and refractive results. The refractive power of the cornea was only one exeption. Long follow-up and randomized prospective studies with a large number of patients are needed.

Effect of femtosecond-assisted intrastromal implantation of MyoRing for keratoconus on corneal asphericity

Purpose The aim of this study was to evaluate the effect of implanting MyoRing into a femtosecond-created corneal pocket on corneal asphericity in patients with keratoconus. Patients and methods This prospective, nonrandomized, interventional clinical study included 38 eyes with keratoconus. Femtosecond-assisted implantation of MyoRing was done for all cases. The intrastromal pocket was 7.4 mm in diameter and deep at a level equal to 80% of central corneal thickness. Corneal asphericity, curvature, thickness, and elevations were evaluated 3 months after surgery. Results The mean age of the patients was 24.53±5.18 years at the time of surgery. The same diameter of the MyoRing was used in all cases. Both uncorrected distance visual acuity and corrected distance visual acuity significantly improved after implantation of the MyoRing. Uncorrected distance visual acuity improved from 0.05±0.01 to 0.31±0.01 and corrected distance visual acuity improved from 0.29±0.14 to 0.34±0.10. The postoperative changes in all measured refractive parameters were significantly better in comparison with the preoperative measures. The mean preoperative spherical equivalent of the refractive error was −9.87±2.91 D, whereas the postoperative spherical equivalent was −0.89±0.30 D. The refractive sphere and cylinder improved also from a preoperative value of −8.31±2.55 and −3.11±1.93 D, respectively, to a postoperative value of −0.46±0.21 and −0.86±0.32 D, respectively. The Q value of anterior corneal surface significantly improved to a less prolate shape, from −0.49±0.11 preoperatively to 0.23±0.01 postoperatively. On the contrary, the Q value of the posterior surface of the cornea showed no statistically significant change after MyoRing implantation. Conclusion MyoRing implantation improved the asphericity of the anterior corneal surface from advanced prolate shape to the optimal prolate Q value of −0.52 and ‘spherical aberration free’ Q value of −0.46. This improvement in corneal asphericity may have a role in increasing the postoperative visual acuity.

Optimization of femtosecond lasers using porcine and human donor corneas before in vivo use

To demonstrate a safe and effective method of optimizing a femtosecond laser upon installation or for a new procedure before use on patients. In this case, specifically for optimizing settings for intrastromal corneal pocket creation for the presbyopic small-aperture corneal inlay (Kamra) and deep laser insitu keratomileusis (LASIK) flaps for the presbyopic hydrogel corneal inlay (Raindrop). Keil LASIK Vision Center, Grand Rapids, Michigan, USA. Experimental study. Human donor corneas were used to optimize femtosecond laser settings after initial optimization with porcine corneas. The laser used was the Femto LDV Z4. Pocket settings optimized for porcine corneas were 12.0mm/s pocket and tunnel at 105% energy; whereas, settings optimized with human donor corneas were 13.0mm/s pocket and tunnel at 110% energy. Settings optimized with human donor corneas were subsequently applied invivo to create pockets for the small-aperture corneal inlay. Further adjustment of settings to 14.0 mm/s pocket at 110% energy was still necessary to optimize pockets. No change in settings was necessary when creating deeper corneal LASIK flaps (ie, the same settings could be used for flaps of 110μm or 180μm). After settings were optimized for porcine corneas, further optimization was necessary before successful corneal incisions could be created invivo for corneal pockets. No further optimization was required when creating deeper corneal flaps for the hydrogel inlay. It is important to emphasize that settings obtained and reported here are not applicable to other femtosecond lasers.

Comparison of the MyoRing implantation depth by mechanical dissection using PocketMaker microkeratome versus Melles\xa0hook via AS-OCT

BackgroundThis paper seeks to evaluate the depth and outcomes of MyoRing implantation using two mechanical dissection procedures including: PocketMaker microkeratome in opposition to the Melles hook method.MethodsThis retrospective study was carried out on 39 eyes of 38 keratoconus patients (28 male and 10 female) with the mean age of 28.97frac{+}{.}10.37 years and had undergone MyoRing implantation by the two mentioned methods. The MyoRing was inserted into the corneal pocket which was made manually in 18 eyes (Melles hook group) or with PocketMaker microkeratome in 21 eyes (PocketMaker group). The mean follow up time was 9.81frac{+}{.}3.7 months with pre-operative and post-operative ophthalmic examination including uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), keratometry readings and central corneal thickness measurement. AS-OCT (Casia, SS-1000, Tomey, Nagoya, Japan) imaging was used to measure MyoRing insertion depth, exactly.ResultsPre-operative and post-operative UCVA (LogMAR) mean change for the PocketMaker and Melles hook groups were recorded at 0.75 ± 0.32 and 0.78 ± 0.33, respectively. Similarly, BCVA (LogMAR) mean change were 0.27 ± 0.22 and 0.23 ± 0.22. Mean keratometry (Kmean) change were 6.06 ± 4.18 and 6.56 ± 3.55 respectively. UCVA change (P = 0.767), BCVA change (P = 0.77) and Kmean change (P = 0.693) showed that there was no statistically significant difference between both groups for any parameter. Depth measurements achieved from AS-OCT images showed that there was no statistically significant difference in pocket depth between two methods of MyoRing implantation (P = 0.413).ConclusionsThe results of Myoring implantation outcomes using mechanical dissection via PocketMaker microkeratome as against Melles hook are comparable.

Femto-second laser (FSL) techniques and consistency in corneal surgery: experimental study

ObjectiveTo investigate the feasibility, effectiveness, and reproducibility of femtosecond laser (FSL) technology in different corneal cuts. DesignExperimental study at the Brandon Regional Health Centre. ParticipantsTwenty two Human Cadaver eyes donated for research and supplied by the eye bank of Manitoba university. MethodsIn this experimental study, the effectiveness and reproducibility of FSL were investigated in different corneal cuts. The corneas were divided into 5 groups: group I for penetrating keratoplasty; group II for anterior lamellar keratoplasty; group III for corneal pockets for inlays; group IV for intracorneal ring tunnels; and group V for corneal cross-linking pockets. Our primary endpoint was the repeatability of planned versus obtained thickness and diameter of the cuts with FSL. A secondary endpoint was the effectiveness and ease of dissection, rated from 0–4, with 4 being the easiest and 0 the most difficult to dissect. ResultsThere was a high correlation between planned and obtained thickness (r = 0.997, p < 0.001) and diameter (r = 0.998, p < 0.001). Both were statistically significant. Linear regression analyses showed that the obtained thickness of corneal cuts in micrometers was significantly predicted by the planned thickness of corneal cuts in micrometers (β = 0.996, t = 56.47, p < 0.001). Likewise, the obtained diameter of corneal cuts in millimeters was significantly predicted by the planned diameter of corneal cuts in millimeters (β = 0.971, t = 70.85, p < 0.001). The surgeons gave 15 out of a total of 22 corneas (68.2%) the maximum score for ease of dissection (Grade 4), where no adhesions were found and the dissection was smooth and steady. Five corneas out of a total of 22 (22.7%) were given a score of 3 of 4 where minor adhesions were found. Two corneas out of a total of 22 (9.1%) were given a score of 2 of 4 where >1 adhesion was found, with some difficulty in separating the cut cornea from the bed. No corneas were given grade 1 or grade 0. No significant differences were obtained for the ease of dissection among the 5 surgery types using Kruskal–Wallis H test (H [4] = 4.971, p > 0.05). ConclusionThe measured corneal-cut geometry correlated well with laser settings in a variety of full- and partial-thickness FSL corneal patterns, including different depths and diameters. This reproducible efficacy and measurement accuracy of the planned versus obtained cuts could have a favourable result on a variety of corneal surgeries. It also yields a favourable ease of dissection of the cut lenticule from the stromal bed.

Complete corneal ring (MyoRing) implantation combined with corneal collagen crosslinking in keratoconus treatment

PurposeTo evaluate functional results of complete corneal ring (MyoRing) implantation with corneal collagen crosslinking (CXL) for progressive keratoconusMethodsMyoRing implantation with corneal CXL was performed in 39 eyes with progressive keratoconus of the II‐III disease degree according to the Amsler classification. Implantation of a MyoRing in the corneal pocket was performed using a PocketMaker microkeratome and corneal intrastromal implantation system. Saturation of the cornea was performed with a solution of 0.1% riboflavin injected into the corneal pocket through the incision tunnel within 10–15 minutes. Standard surface UV irradiation (370 nm, 3 mW/cm2) was carried out for 30 minutes. The follow‐up was 36 months.ResultsSignificant improvements in uncorrected distance visual acuity and corrected distance visual acuity were observed. Keratometry was reduced for 9.43 D, the spherical equivalent decreased from from 9.43 D to 6.25 D. The cylinder decreased to 3.31. Corneal thickness decreased from baseline (from 426.93 ± 46.58 μm to 401.24 ± 39.12 μm) 36 months postoperatively, which corresponds with pachymetry reduction after conventional CXL. Dynamic observation after 36 months showed stabilization of clinical and functional results.ConclusionsCombination of CXL and MyoRing implantation was effective for keratoconus treatment. Complete corneal ring implantation combined with corneal collagen crosslinking allows not only correct the keratoconus followed ametropia but also slow down the progression of the disease.

Complete corneal ring (MyoRing) implantation versus MyoRing implantation combined with corneal collagen crosslinking for keratoconus: 3-year follow-up

PurposeTo estimate the effectiveness of complete corneal ring (MyoRing) implantation compared with MyoRing implantation combined with corneal collagen crosslinking (CXL) for keratoconus treatment for 36 months follow-up.DesignRetrospective cohort study.Materials and methodsMyoRing implantation was performed in a series of 78 patients (80 eyes) with keratoconus II–III Amsler classification, of these 39 eyes had MyoRing implantation combined with CXL. Implantation of a MyoRing in the corneal pocket was performed using a PocketMaker microkeratome and corneal intrastromal implantation system. During CXL, riboflavin solution 0.1% was injected into the corneal pocket through the incision tunnel and standard surface UVA irradiation (370 nm, 3 mW/cm2) was then applied from 5-cm distance for 30 min.ResultsSignificant improvements in uncorrected distance visual acuity and corrected distance visual acuity were observed for both groups, which was relatively better 12 months after procedure in MyoRing alone group; however, in 36 months there was no difference between groups. Keratometry was reduced in both groups; after MyoRing implantation for 8.45 D and MyoRing + CXL for 9.43 D, the spherical equivalent decreased from 8.45 to 7.72 D and from 9.43 to 6.25 D, respectively. The cylinder decreased to 3.33 D with MyoRing alone and to 3.31 D with MyoRing + CXL. Corneal thickness remained nearly unchanged (from 433.69 ± 38.76 to 434.21 ± 34.98) in MyoRing group and decreased from baseline (from 426.93 ± 46.58 to 401.24 ± 39.12 µm) in MyoRing + CXL group 36 months postoperatively, which corresponds with pachymetry reduction after conventional CXL.ConclusionBoth MyoRing implantation and MyoRing combined with CXL were effective for treating keratoconus. At 36 months, there were slightly better outcomes in MyoRing + CXL group; however, in MyoRing alone group visual and refractive outcomes were stable overtime.

Pathogenic role and therapeutic potential of pleiotrophin in mouse models of ocular vascular disease.

Angiogenic factors play an important role in the pathogenesis of diabetic retinopathy (DR), neovascular age-related macular degeneration (nAMD) and retinopathy of prematurity (ROP). Pleiotrophin, a well-known angiogenic factor, was recently reported to be upregulated in the vitreous fluid of patients with proliferative DR (PDR). However, its pathogenic role and therapeutic potential in ocular vascular diseases have not been defined in vivo. Here using corneal pocket assays, we demonstrated that pleiotrophin induced angiogenesis in vivo. To investigate the pathological role of pleiotrophin we used neutralizing antibody to block its function in multiple in vivo models of ocular vascular diseases. In a mouse model of DR, intravitreal injection of pleiotrophin-neutralizing antibody alleviated diabetic retinal vascular leakage. In a mouse model of oxygen-induced retinopathy (OIR), which is a surrogate model of ROP and PDR, we demonstrated that intravitreal injection of anti-pleiotrophin antibody prevented OIR-induced pathological retinal neovascularization and aberrant vessel tufts. Finally, pleiotrophin-neutralizing antibody ameliorated laser-induced choroidal neovascularization, a mouse model of nAMD, suggesting that pleiotrophin is involved in choroidal vascular disease. These findings suggest that pleiotrophin plays an important role in the pathogenesis of DR with retinal vascular leakage, ROP with retinal neovascularization and nAMD with choroidal neovascularization. The results also support pleiotrophin as a promising target for anti-angiogenic therapy.

TO STUDY THE EFFECTS OF INTRASTROMAL CORNEAL RING GEOMETRY AND SURGICAL CONDITIONS ON THE POSTSURGICAL OUTCOMES THROUGH FINITE ELEMENT ANALYSIS

Intrastromal corneal ring (ICR) is a transparent circular implant inserted in the cornea to provide structural support in an attempt to alleviate preexisting refractive errors. This is a surgical procedure whose success depends on control parameters such as, ICR geometry which includes ICR thickness and diameter, and surgical conditions which includes ICR implantation depth and diameter of corneal pocket. This research utilizes finite element (FE) analysis techniques to develop a high fidelity and computationally efficient three-dimensional axisymmetric cornea model to study the relative effects of ICR implant geometry and surgical conditions on the postsurgical shape of the cornea utilizing corneal apical displacement results. The FE analysis results indicate that ICR implantation reduces myopia, and the amount of myopic rectification is dependent on the control parameters which include ICR geometry and surgical conditions. The results show that an increase in ICR thickness leads to an increase in myopic rectification, whereas an increase in ICR radius leads to a decrease in myopic rectification. ICR implantation depth analysis results suggest that corneal depth of 40–75% provides steady myopic rectification. Corneal pocket diameter analysis revealed that smaller corneal pockets lead to increase in myopic rectification. Overall, the FE model results are in qualitative agreement with published clinical studies. Finally, the combined impact of the control parameters on myopic rectification was studied by conducting a sensitivity analysis and an equation relating myopic rectification with control parameters was developed utilizing simple linear regression analysis.

Six-month visual outcomes for the correction of presbyopia using a small-aperture corneal inlay: single-site experience.

ObjectiveThe objective of this study was to describe 6-month postoperative efficacy and safety outcomes after monocular KAMRA corneal inlay implantation in emmetropic presbyopic patients.Study designThis study followed a retrospective chart analysis.SettingThis study was performed at Hoopes Vision in Draper, UT, USA.Subjects and methodsFifty-seven patients met the inclusion criteria of this study and underwent KAMRA corneal inlay implantation following the approval of the United States Food and Drug Association between May 2015 and April 2016 at a single site. Surgery involved femtosecond laser-created corneal pockets of various depths. Efficacy, safety, and patient satisfaction reports were analyzed at 3 and 6 months.ResultsAt 6 months follow-up, the monocular uncorrected near visual acuity (UNVA) was Jaeger (J) 4 (20/32), the mean uncorrected distance visual acuity was 20/25, and the mean corrected distance visual acuity was 20/20. At 6 months, 71% of patients with a pocket depth of ≥250 μm had a UNVA of 20/20 or better, whereas only 22% of patients with a shallow pocket depth of <250 μm had a UNVA of 20/20 or better. There was no statistical difference in UNVA at 6 months between virgin eyes and post-LASIK eyes. One patient had an explant and five patients underwent inlay recentration, all of which resulted in improved visual acuity. At 6 months, 72% of patients reported some level of satisfaction, 26% of patients reported being “not dependent” on reading glasses, and 62% of patients reported being able to do most things in bright light without reading glasses.ConclusionFor patients with emmetropic presbyopia, the KAMRA inlay is a viable treatment option resulting in improved UNVA. Increased pocket depth may be associated with better postoperative outcomes. Safety rates are high, while explantation and recentering rates are low. Overall, patient satisfaction of the KAMRA inlay is good.

Long-term results of MyoRing treatment of keratoconus

PurposeTo study long-term results of MyoRing treatment of keratoconus. MethodsRetrospective study of MyoRing implantation into a corneal pocket for keratoconus. ResultsCorneal thickness at the thinnest point remained unchanged, SIM K's, manifest sphere and cylinder were significantly improved at the first follow-up 9 months postoperatively and remained stable until the last follow-up about 5 years after surgery. Uncorrected and corrected distance visual acuity (UDVA, CDVA) were significantly improved at the first follow-up 9 months postoperatively and were further ameliorated until the last follow-up about 5 years after surgery. ConclusionThe treatment was safe and effective with continuing improvement of visual acuity during the 5 years after surgery.

PKN3 is the major regulator of angiogenesis and tumor metastasis in mice.

PKN, a conserved family member related to PKC, was the first protein kinase identified as a target of the small GTPase Rho. PKN is involved in various functions including cytoskeletal arrangement and cell adhesion. Furthermore, the enrichment of PKN3 mRNA in some cancer cell lines as well as its requirement in malignant prostate cell growth suggested its involvement in oncogenesis. Despite intensive research efforts, physiological as well as pathological roles of PKN3 in vivo remain elusive. Here, we generated mice with a targeted deletion of PKN3. The PKN3 knockout (KO) mice are viable and develop normally. However, the absence of PKN3 had an impact on angiogenesis as evidenced by marked suppressions of micro-vessel sprouting in ex vivo aortic ring assay and in vivo corneal pocket assay. Furthermore, the PKN3 KO mice exhibited an impaired lung metastasis of melanoma cells when administered from the tail vein. Importantly, PKN3 knock-down by small interfering RNA (siRNA) induced a glycosylation defect of cell-surface glycoproteins, including ICAM-1, integrin β1 and integrin α5 in HUVECs. Our data provide the first in vivo genetic demonstration that PKN3 plays critical roles in angiogenesis and tumor metastasis, and that defective maturation of cell surface glycoproteins might underlie these phenotypes.